Alkoxide phenoxide

The range of nueleophiles whieh have been observed to partieipate in nueleophilie aromatie substitution is similar to that for S[, 2 reactions and includes alkoxides, phenoxides, sulftdes, fluoride ion, and amines. Substitutions by earbanions are somewhat less common. This may be because there are frequently complications resulting from eleetron-transfer proeesses with nitroaromatics. Solvent effects on nucleophilic aromatic substitutions are similar to those discussed for S 2 reactions. Dipolar... 

The reactions of 2- and 4-cyanoquinazolines are similar to those of the chloro compounds. Thus the cyano group can be replaced by alkoxide, phenoxide, substituted amino, and hydrazino groups substitution of the 4-cyano takes place more readily than that of the 2-cyano group.The nitrile substituent can also be hydrolyzed to an alkoxycarbonyl and amide group/ ... 

Non-cyclopentadienyl single-site lanthanide alkoxides mostly feature N-donor-based ancillary ligands. Examples include bulky bis(arylamidinate)-yttrium(III) alkoxides, phenoxides and amides such as complexes (307)-(309), which initiate the ROP of LA.892 However, control over molecular weight is poor and polydispersities are broad (typically >1.5), with the exception of (309) in the presence of exogenous benzyl alcohol. 

Analogous alkoxides, phenoxides, and carboxylates will also initiate the ROP of epoxides, all forming propagating alkoxide species.779 Block copolymers of epoxides with /3-butyrolactone have been prepared via the addition of EO or PO to living poly(ester) chains.782 The oxygen-bound enolate of living PMMA will also react with epoxides to yield diblocks such as PEO-b-PMMA and PPO-b-PMMA (Mn= 12,800, Mw/Mn = 1.16) 787... 

Displacement by cyanide works particularly well, and many other nucleophilic substitution reactions are enhanced by PTC. Most monovalent anions can be transferred, including alkoxides, phenoxides, thiocyanates, nitrates, nitrites, superoxides and all of the halides. Divalent anions are usually too hydrophilic to be transferred into the organic phase. 

Nucleophilic Substitution Alkyl, Alkoxide/Phenoxide, Halides and Amido... 

Halides are displaced by a variety of nucleophiles including alkoxides, phenoxides, thiolates, cyanide, and amines. 4-Halogenobenzofurazans yield either 4-or 5-substituted products resulting from normal ipso or cine reactions, and 5-halogeno derivatives react similarly. An addition lim-ination AE mechanism has been invoked to explain the cine products, whereas ipso substitution can result from both AE and Sj.,Ar pathways (Scheme 14) <81MI 405-02). 

Although there have been few new developments in the period since 1993, halogenopyrazines 42 have been convenient precursors for a variety of pyrazine derivatives. For example, the halogenopyrazines 42 are cyanated by palladium-catalyzed cross-coupling with alkali cyanide or by treatment with copper cyanide in refluxing picoline, to yield cyanopyrazines 48. Alkoxypyrazines 49 are produced by treatment with alkoxide-alcohol, and aminopyrazines 50 are prepared by amination with ammonia or appropriate amines. The nucleophilic substitution of chloropyrazine with sodium alkoxide, phenoxide, alkyl- or arylthiolate is efficiently effected under focused microwave irradiation <2002T887>. 

The organic compounds of potassium include many oxycompounds, such as salts of organic acids, alcohols and phenols (alkoxides, phenoxides, etc.). A few potassium-carbon linked compounds have been reported, such as a phenyhsopropyl potassium. C6H5C3H7K, and a carbonyl compound of unknown composition. Kx(f 0)Y. The adduct of ethyl potassium and diethyl-zinc is a true salt, K2[Zn(C2H5)4], potassium tetraethylzincate. 

The most numerous organic compounds of rubidium are those of oxy compounds, such as the salts of organic adds, the alcohols and phenols (alkoxides. phenoxides, etc.). An ethyl rubidium-zinc diethyl adduct has been reported, RbZn Hs), which is certainly the true salt, rubidium triethylzincate, RbfZnt CsHs ],... 

In some cases, control of the stoichiometry allows the isolation of mixed alkoxide-phenoxide derivatives.87 In other cases only partial substitution can be achieved either for steric89 or electronic reasons88 (equations 21 and 22). 

Know the meaning of alkoxide, phenoxide, oxonium ion, alkyloxonium ion. 

Basic catalysts crown ether alkoxide/phenoxide... 

Silyl Alkoxides, Phenoxides, and Their Sulfur Analogs... 

Unlike ordinary ethers, epoxides can be cleaved under alkaline conditions. Here it is the epoxide itself, not the protonated epoxide, that undergoes nucleophilic attack. The lower reactivity of the non-protonated epoxide is compensated for by the more basic, more strongly nucleophilic reagent alkoxide, phenoxide, ammonia, etc. 

This early work is summarised in Krause and von Grosse s Organometallische Che-mie which was published first in 1937,11 and which described examples of tetraalkyl-and tetraaryl-stannanes, and of the organotin halides, hydrides, carboxylates, hydroxides, oxides, alkoxides, phenoxides, R2Sn(II) compounds (incorrectly), distannanes (R3SnSnR3), and oligostannanes (RiSn) . 

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